21-11-2012, 01:58 PM
To study the block diagram and working of GSM mobile phone
[attachment=40524]
THEORY:
RF section:
This is where the RF signal is filtered and down converted to analog baseband signals. It is also where analog base band signals are filtered and then unconverted and amplified to RF.
A simplified block diagram of GSM mobile phone
Keyboard:
HDa 12 has 16 keys and uses 4 rows and 5 columns. Scanning is used for keyboard reading. Rows and columns are connected to MAD2WD1 interface. In addition, serial resistors of 1K are inserted between the Keyboard Rows and the MAD.
Analog Base band / Voice band Codec:
This is where analog base band signals from RF receiver section are filtered, sampled, and digitized before being fed to the DSP section. It is also where coded speech digital information from DSP section is sampled and converted to analog base band signals, which are then fed to the RF transmitter section. This is where voice speech from the microphone is digitized and coded to a certain bit rate (13kbps for GSM) using the appropriate coding scheme (balance between perceived quality of the compressed speech and the overall cellular system capacity and cost). It is also where the received voice call binary information are decoded and converted in the speakerphone.
DSP / Microprocessor:
The digital signal processor (DSP) is a highly customized processor designed to perform signal manipulation calculations at high speed. The microprocessor handles all of the housekeeping chores for the keyboard and display; deals with command and control signaling with the base station and also coordinates the rest of the functions on the board.
Flash Memory, ROM, SRAM (SIM card):
The ROM, SRAM, and Flash memory chips provide storage for the phone’s operating system and customizable features, such as the phone directory. The SIM card belongs to this category; it stores the subscriber’s identification number and other network information.
Power Management / DC- DC:
This section regulates from the battery all the voltages required to the different phone sections. It contain a charging section and power management IC.
SIM card:
A SIM card is basically a Smart Card used to store the identifying key for a mobile. Smart Card defines the physical and electrical protocols for a plastic ‘chip card’ used to store data. A Smart Card can hold much more data then a simple magnetic strip as it have an embedded memory chip to store data, and an embedded microprocessor to interact during a transaction. Smart Card uses normal TTL switching levels. Smart Card comes in two different interface types; a contact type and a contact less type.
[attachment=40524]
THEORY:
RF section:
This is where the RF signal is filtered and down converted to analog baseband signals. It is also where analog base band signals are filtered and then unconverted and amplified to RF.
A simplified block diagram of GSM mobile phone
Keyboard:
HDa 12 has 16 keys and uses 4 rows and 5 columns. Scanning is used for keyboard reading. Rows and columns are connected to MAD2WD1 interface. In addition, serial resistors of 1K are inserted between the Keyboard Rows and the MAD.
Analog Base band / Voice band Codec:
This is where analog base band signals from RF receiver section are filtered, sampled, and digitized before being fed to the DSP section. It is also where coded speech digital information from DSP section is sampled and converted to analog base band signals, which are then fed to the RF transmitter section. This is where voice speech from the microphone is digitized and coded to a certain bit rate (13kbps for GSM) using the appropriate coding scheme (balance between perceived quality of the compressed speech and the overall cellular system capacity and cost). It is also where the received voice call binary information are decoded and converted in the speakerphone.
DSP / Microprocessor:
The digital signal processor (DSP) is a highly customized processor designed to perform signal manipulation calculations at high speed. The microprocessor handles all of the housekeeping chores for the keyboard and display; deals with command and control signaling with the base station and also coordinates the rest of the functions on the board.
Flash Memory, ROM, SRAM (SIM card):
The ROM, SRAM, and Flash memory chips provide storage for the phone’s operating system and customizable features, such as the phone directory. The SIM card belongs to this category; it stores the subscriber’s identification number and other network information.
Power Management / DC- DC:
This section regulates from the battery all the voltages required to the different phone sections. It contain a charging section and power management IC.
SIM card:
A SIM card is basically a Smart Card used to store the identifying key for a mobile. Smart Card defines the physical and electrical protocols for a plastic ‘chip card’ used to store data. A Smart Card can hold much more data then a simple magnetic strip as it have an embedded memory chip to store data, and an embedded microprocessor to interact during a transaction. Smart Card uses normal TTL switching levels. Smart Card comes in two different interface types; a contact type and a contact less type.